I am only a software guy.
I have been following this list since the R3000 days. I think that
the original idea was to create a reasonably powerful Unix-machine
that is joy to program. But above all it should be affordable.
Now we're talking about $1000-$5000 motherboards etc... well I surely
can't afford to build a machine that costs so much.
Now, wouldn't the easiest & cheapest way to provide a RISC platform
be a CPU card for existing PCI or VESA based PC?
The card would include CPU, DRAM, bus interface and possibly
L2 cache. Unix kernel and user processes would all run on the
card. The PC would be used as an intelligent I/O subsystem and
The programming interface between the Card and the PC could
be defined cleanly in a message-passing fashion (Mach). The machine
would be basically a heterogenous asymmetric multiprocessor.
All the programming and OS-stuff would happen in the clean
RISC environment, only device drivers and X-server would be
implemented in the revolting PC-environment.
The benefits I can think of are:
-there exist plenty of public domain device drivers for
PC motherboards (for example Linux drivers)
-X-servers for PC:s exist
-All ISA-, VESA- or PCI-cards would work because they
would operate in true Intel environment.
-Hardware related work would be minimized, and we could
concentrate on the software developement, that can be
done by more people than hardware hacking.
-I/O would be quite efficient because all PC-RAM could
be utilized for buffers and X-window backup storage etc...
-existing PC-hardware could be utilized.
The possible drawbacks are:
-Unpleasent developement environment for device drivers.
-the bus interface could be a bottleneck for some applications.
I know these kind of cards have existed. An old 68000 card
from Sritek for PC-XT come to mind. It was very fast in its time.
I have seen a Sparc-2 card for PC too. And some i860 cards
exist too. They all use ISA bus though.